Most ancient of all mysteries
This hymn is from the prolific Victorian writer Frederick William Faber (1814-1863). He was born in Yorkshire, educated at Oxford and elected a Fellow of the University in 1837. He was of Huguenot descent, one of his ancestors having fled from France to England on the Revocation of the Edict of Nantes. Faber was brought up in the strictest school of Calvinism, but whilst at Oxford he came under the influence of Newman, which drew him to the other extreme. He was ordained into the Church of England in 1838 and became Rector of Elton. However, by 1845 he had moved to Birmingham to set up a small religious community 'Brothers of the Will of God', later shortened to the 'Wilfridians' because Faber took for himself the name Brother Wilfrid. In 1848, he joined the Oratory of St Philip Neri, under Newman. In the following year he established a branch of that order in London, which developed into the Brompton Oratory. Faber wrote over 150 hymns, intended both for devotional reading, and to encourage the singing of hymns in the Catholic Church.
There a few hymns appointed for Trinity Sunday. This hymn seems to have fallen in and out of favour through the various editions of the mainstream hymnals. It does not appear in Hymns Ancient and Modern Standard, or New Standard, but does appear in the intervening Revised Edition. It appears in the English Hymnal, but in a different verse arrangement to the New English Hymnal. The first verse of the EH edition likens us to 'worms of earth', so it is not too surprising that verse 2, 'Most ancient of all mysteries...' became the favoured starting point.
Tune - St Flavian
The tune St Flavian is from The English Psalter (Day's Psalter), 1562. The common metre tune is the first half, slightly altered, of the double common metre tune of Psalm 132. It was first found in Redhead's Ancient Hymn Melodies, 1859, where it is erroneously attributed to him. Richard Redhead (1820-1901) was organist of All Saint's Margaret Street from 1835-1864, and his collections of hymns were a major influence on the musical side of the Catholic Revival.